What is the stain procedure that malachite green is used for? In our lab, we had 4 exams plus we had to turn in 5 formal lab reports and do an Unknown project given 2 samples. The Gram negative unknown was identified to be Pseudomonas aeruginosa. For maximum magnification 1000X or oil immersion , rotate the blue-striped 40X objective slightly out of position and place a drop of immersion oil on the slide. Lots of fun, especially when you have good dichotomous keys to work from. Name the labeled structure on the microscope, and its function.
The citrate test was positive and the glycerol test was negative. Please see Code of Conduct in the most recent Student Handbook. A volume of one cubic inch is sufficient to contain approximately nine trillion average-sized bacteria. Metric Length and Fluid Volume The study of microorganisms necessitates an understanding of the metric system of length. Lab Manual for General Microbiology. It would take over 18,000,000 average-sized cocci lined up edge-to-edge to span the diameter of a dime! Tests for mixed acid fermentation.
If you had a culture contamination, potentially you had a problem because some test would turn out positive when they should be and negative when they shouldn't be, and that can get really confusing so you have to use the weight of evidence and try to determine which is which. Determine the number of viruses per ml. Both you and your partner wash your hands with disinfectant soap and sanitize your hands. It is important to know what microorganisms are growing in each tube or on each plate. I then ran a couple more tests to confirm the fact that I had that particular specific organism.
A negative Urea test removed K. Measures absorbance of light, directly related to cell density. Light adjustment using the iris diaphragm lever is critical to obtaining proper contrast. You had to apply everything you have learned throughout the semester in order to complete the final exam practical. Materials and Methods At the beginning of this project, the professor handed each student a numbered test tube containing two unknown bacteria one Gram positive and one Gram negative. Name this hemolytic reaction---alpha, beta, or gamma? Both the glass and the oil have a refractive index of 1. This chemical acts as a growth inhibitor for many other bacteria and some fungi, which allows B.
Sterilize the inoculating loop after use. Thirdly, several of the tests had to be repeated because the first stock plate of P. At this point, both bacteria were successfully isolated and plated on stock nutrient agar plates. Furthermore, some probiotic companies are using B. A negative casein test removed S.
Is this organism + or - for caseinase? Give the gram reaction and shape of the bacterium. Secure the slide between - not under- the slide holder arms of the mechanical stage Fig. If higher magnification is desired, simply rotate the blue-striped 40X objective into place total magnification of 400X and the specimen should still be in focus. General Directions Always familiarize yourself in advance with the exercises to be performed. Do you have your syllabus yet? Heat fix the smear by putting it on the slide warmer for one minute. And, a negative methyl red test removed B. The only slight issue was that B.
What is the total magnification if you were viewing a specimen using this objective lens? Overall, I quite enjoyed microbiology, but I don't think that I would've ever wanted to make it my life's work. The test tube used in this study was tube 109. Some other commercial applications of B. What do you call these filaments found in fungi? That kind of testing would've gone faster, but we would not have been able to prove quite readily whether or not we understood aseptic technique. There were 34 isolated colonies present, all of which showed the same growth pattern. After a second round of tests, all of the results matched up with the expected results of P. However, the researcher felt it was important to perform a battery of tests in order to confidently conclude that the Gram positive unknown was indeed B.
Also, if high magnification is to be used, more light is needed. Return all equipment, reagents, and other supplies to their proper places at the end of each lab period. An explanation of each test and the results are in Table 1 for the Gram positive bacteria and Table 2 for the Gram negative bacteria. You must wear shoes that cover the tops of your feet to prevent injury from broken glass, spilled chemicals, and dropped objects. Chart 1 details the sequence of tests performed on the Gram positive bacteria and Chart 2 details the sequence of test performed on the Gram negative bacteria. The basic unit for fluid volume is the liter l , which is approximately 1.